i didn't know ________at that timeA.where does he come fromB.if janet will help me with cookingC.the light travels faster than the soundD.what was the girl doing

i didn't know ________at that timeA.where does he come fromB.if janet will help me with cookingC.the light travels faster than the soundD.what was the girl doing
i didn't know ________at that time
A.where does he come from
B.if janet will help me with cooking
C.the light travels faster than the sound
D.what was the girl doing

i didn't know ________at that timeA.where does he come fromB.if janet will help me with cookingC.the light travels faster than the soundD.what was the girl doing
C
从句应该是陈述语序,AD错了
时态应和前面的didn't一致,都是过去时,AB错.C没错,因为C中说的是一般公理或道理,这种不用过去时

C
因为这是宾语从句,后接的句子要用陈述句子,所以A/D 可以先排除
B要选的话will应该写成would
C是客观事实，光速比声音快，无论主句是什么时态，从句都要用一般现在时

C

D

C宾语从句用陈述句式.且“光的速度比声音的快”属于真理事实类,为一般现在时.其余答案应与主句时态一致

b.
a和d肯定不对了.从句不倒装的.b和c里面选.我认为c不对.c中比较对象应该是
the light travels 和 the sound travels.光速和声速.